1. Field of the Invention
This invention is related to computers and virtual machines used with computers.
2. Description of the Related Art
Computers have become a ubiquitous part of modern society, and users have employed them for numerous demanding and often critical tasks. As the complexity and number of application programs for computers continues to grow, it is often the case that a computer employing a single processor (or central processing unit, CPU) is insufficient to execute the programs with the desired performance. Some computers implement multiple processors in a symmetric multiprocessing (SMP) configuration, sharing a common memory. However, bandwidth limits and the physical limits on the size of a single memory system limit the number of processors in an SMP configuration that can effectively share the memory. Another system configuration that has been used in the past is a cache-coherent, non-uniform memory access (ccNUMA) system. In ccNUMA systems, dedicated hardware is used to connect multiple nodes (each having processors and memory, and optionally input/output (I/O) devices) into a computer system. The dedicated hardware handles cache coherency, and also handles access by one node to another node's memory. The nodes are typically interconnected by a proprietary, high speed interconnect. The ccNUMA configuration may provide scalable performance, but is often expensive due to the dedicated hardware and proprietary interconnect used in these systems. An exemplary ccNUMA system is the Sequent computer system manufactured by IBM Corporation.